This is a comprehensive program to study the immunopathogenesis of renal disease. C3 nephritic factor will be examined by a structural approach and its production in animals will be attempted. Prevention of lupus nephritis in NZB/W mice and its treatment will be pursued with tolerogens to DNA and corticosteroids. Strain differences in rats to induction of autologous immune complex nephritis will be related to differences in T cell subsets and T cell suppressor activity. Malignant transitional epithelium will be examined for synthesis of Clq, the first component of complement. Ultrastructure of glomeruli will be studied in normal and nephritic rats.